Engine temperature fluctuates in Dodge Spirit

Ok, so I finally put a pressure tester on the radiator and it did NOT hold pressure. It turns out there was a leak in the radiator so I replaced it with a new one (about 100 bucks). The heater was also not working well so I removed the hoses, flushed and back-flushed the heater core several times. Lots of nasty stuff came out of it especially the first time I back-flushed. I now have a normal HOT heater, good and stable engine temperature and no fluctuations. I also do not smell any anti-freeze. The car is finally back to normal now.